Slow connection on Linux xinetd Telnet when logging is enabled

Problem: Telnet sessions to a Linux machine (in my case CentOS 6.8) via xinetd take half a minute or longer before showing the login prompt

Solution: Disable USERID logging, for xinetd telnet this is located in /etc/xinetd.d/telnet file

Example:

service telnet
{
        disable         = no
        flags           = REUSE
        socket_type     = stream
        wait            = no
        user            = root
        server          = /usr/sbin/in.telnetd
        log_on_failure  = PID HOST USERID
        log_on_success  += PID HOST EXIT
}

Just remove USERID if it is declared in any place and save the file, after which you should restart xinetd

Source:

http://www.tomshardware.co.uk/forum/4447-50-improving-response-time-network-requests